March 2022
Intermediate to advanced
522 pages
13h 52m
Chinese
Content preview from Python语言及其应用（第2版）
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370
｜
第
19
章
如果向
basicConfig()
提供格式化字符串，则可以修改消息的输出格式：
>>> import logging
>>> fmt = '%(asctime)s %(levelname)s %(lineno)s %(message)s'
>>> logging.basicConfig(level='DEBUG', format=fmt)
>>> logger = logging.getLogger('bunyan')
>>> logger.error("Where's my other plaid shirt?")
2014-04-08 23:13:59,899 ERROR 1 Where's my other plaid shirt?
让
logger
再次将输出发送至屏幕，但这次修改了消息格式。
logging
模块能够识别
fmt
格式化字符串中的多个变量名称。这里用到了
asctime
（
ISO
8601
字符串形式的日期和时间）
、
levelname
、
lineno
（行号）和
message
本身。除此之外，
还有其他内建变量，你也可以提供自己的变量。
本节只是介绍了
logging
模块的皮毛。你可以同时在多个地方以不同的优先级和格式记录
日志。该模块灵活性颇高，但有时是以牺牲简单性为代价的。
19.10
优化
Python
通常已经足够快了，不过并非总是如此。在很多情况下，你可以使用更好的算法或
数据结构来提高速度。诀窍在于知道从何处入手。即便是程序员老手也会经常猜错地方。
你需要像细心的绗缝师一样，在裁剪前先测量好。这就引出了计时器。 ...
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